1. Field of the Invention
The present invention is generally related to an engine control system and, more particularly, to an engine control system that uses a manually controlled torque demand signal to determine the appropriate engine control strategies relating to air supply, fuel supply, and ignition control.
2. Description of the Prior Art
Most known engine control systems rely on a manually controlled throttle position setting that determines the rate of air supply to the engine. Other variables, such as fuel supply and ignition timing, are dependent on the manually controlled rate of air supply to the engine. These parameters are typically stored as a function of load and engine speed.
U.S. Pat. No. Re34,803, which issued to Chasteen on Dec. 6, 1994, describes a two-cycle engine with an electronic fuel injection system. The fuel injection controlling device comprises an air manifold, a throttle valve, a fuel injector, a fuel supply system including a fuel pump, a battery voltage sensor, an air temperature sensor, an engine speed sensor, a timing sensor, a barometric pressure sensor, a throttle position sensor, a first data processor for receiving and processing sensing signals for determining fuel injector duration and timing the fuel pump operating speed, a first data processor temperature sensor for sensing the relative temperature of certain electronic components in the first data processor, a heater operatively associated with the first data processor electronic components for selectively heating the electronic components, and a second data processor operable independently of the first data processor for receiving an electronic component temperature sensing signal and for generating a control signal to the heater responsive thereto for heating the components when the temperature thereof is below a predetermined minimum value.
U.S. Pat. No. 5,749,344, which issued to Yoshiume et al on May 12, 1998, describes a fuel supply control system for an internal combustion engine. A throttle valve opening and an engine rotational speed are detected to estimate intake air pressure of an engine. Fuel consumption is estimated from the estimated intake air pressure. The fuel pump drive voltage is calculated from estimated intake air pressure and estimated fuel consumption through a data map. This map is set in advance from data measured experimentally. By thus driving the fuel pump, it can be controlled at an earlier relative time by taking the response time delay of the control system and the fuel pump into consideration.
U.S. Pat. No. 5,626,120, which issued to Akatsuka on May 6, 1997, describes an engine control system and method. A control system and method for an internal combustion engine that employs a throttle position sensor and an engine speed sensor is described. The initial fuel air ratio control is based upon a map experimentally determined from throttle position and engine speed settings for optimum performance. However, in the event the throttle position sensor is deemed to be inaccurate, then another method is utilized for engine control purposes. In most embodiments, a map is also used in the other way.
U.S. Pat. No. 5,813,374, which issued to Chasteen on Sep. 29, 1998, describes a two cycle engine with an electronic fuel injection system. A fuel injection system for a two stroke engine comprises an air manifold, a throttle valve, a fuel injector, a fuel supply system including a fuel pump, a battery voltage sensor, an air temperature sensor, an engine speed sensor, a timing sensor, a barometric pressure sensor, a throttle position sensor, a first data processor for receiving and processing sensing signals for determining fuel injector duration and timing and fuel pump operating speed, a first data processor temperature sensor for sensing the relative temperature of certain electronic components in the first data processor, a heater operatively associated with the first data processor electronic components for selectively heating the electronic components, and a second data processor operable independently of the first data processor for receiving an electronic component temperature sensing signal and for generating a control signal to the heater responsive thereto for heating the components when the temperature thereof is below a predetermined minimum value.
U.S. Pat. No. 4,779,581, which issued to Maier on Oct. 25, 1988, describes a dual fuel injection system for two stroke internal combustion engines. The engine comprises a cylinder, a crankcase extending from the cylinder, a piston reciprocal in the cylinder and defining, with the cylinder, a variable volume combustion chamber and defining, with the crankcase, a crankcase chamber having a volume which varies inversely with respect to the volume of the combustion chamber, a transfer passage communicating, subject to piston movement, between the crankcase chamber and the combustion chamber, an air intake passage extending from the crankcase chamber and including therein a throttle valve movable between opened and closed positions to control engine speed, a reed valve located between the air intake passage and the crankcase chamber for controlling communication between the air intake passage and the crankcase chamber, a first fuel injector communicating with the transfer passage, a second fuel injector communicating with the air intake passage between the reed valve and the throttle valve, and a controller for actuating the first fuel injector to supply fuel to the transfer passage at relatively low engine speeds and for actuating the second fuel injector to supply fuel to the intake passage at relatively high engine speeds.
U.S. Pat. No. 5,848,582, which issued to Ehlers et al on Dec. 15, 1998, discloses an internal combustion engine with barometric pressure related start of air compensation for a fuel injector. The control system for a fuel injector system for an internal combustion engine is provided with a method by which the magnitude of the start of air point for the injector system is modified according to the barometric pressure measured in a region surrounding the engine. This offset, or modification, of the start of air point adjusts the timing of the fuel injector system to suit different altitudes at which the engine may be operating.
The United States patents described above are hereby expressly incorporated by reference in the description of the present invention.
In marine propulsion and control systems that utilize electronic throttle control systems, no cable connection is provided between the throttle handle, which is controlled by an operator of the marine vessel, and the internal combustion engine that provides the propulsive force for the vessel. It would therefore be significantly beneficial if an engine control system could be provided which specifically selects the rates of supply of both fuel and air to the cylinders of the engine and, in addition, determines the ignition timing and energy parameters for the engine.